diff --git a/ChangeLog b/ChangeLog
index a149c39daa..72426a3196 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+Fri Feb 24 18:21:55 2012  Hiroshi Nakamura  <nahi@ruby-lang.org>
+
+	* test/zlib/test_zlib.rb (TestZlibGzipReader#test_encoding): Add
+	  encoding testcases for GzipReader#read.  read() emits
+	  Encoding.default_external in contrast to read(size) emits BINARY.
+	  See also: http://bugs.jruby.org/6208
+
 Fri Feb 24 17:56:39 2012  URABE Shyouhei  <shyouhei@ruby-lang.org>
 
 	* test/ruby/test_literal.rb (TestRubyLiteral#test_special_const):
diff --git a/test/zlib/test_zlib.rb b/test/zlib/test_zlib.rb
index b526d24df9..1e3d77160c 100644
--- a/test/zlib/test_zlib.rb
+++ b/test/zlib/test_zlib.rb
@@ -749,6 +749,22 @@ if defined? Zlib
         end
       end
     end
+
+    def test_encoding
+      t = Tempfile.new("test_zlib_gzip_reader_encoding")
+      t.binmode
+      content = (0..255).to_a.pack('c*')
+      Zlib::GzipWriter.wrap(t) {|gz| gz.print(content) }
+      t.close
+
+      read_all = Zlib::GzipReader.open(t.path) {|gz| gz.read }
+      assert_equal(Encoding.default_external, read_all.encoding)
+
+      # chunks are in BINARY regardless of encoding settings
+      read_size = Zlib::GzipReader.open(t.path) {|gz| gz.read(1024) }
+      assert_equal(Encoding::ASCII_8BIT, read_size.encoding)
+      assert_equal(content, read_size)
+    end
   end
 
   class TestZlibGzipWriter < Test::Unit::TestCase